1. Field of the Invention
The present invention relates to a fuel tank closure for attachment on a tank filler pipe of a motor vehicle. More specifically, the invention relates to a fuel tank closure with a coupling part for actuating a movable closure part which selectively opens or closes the access to the interior of the tank filler pipe.
2. Description of Related Art
In the following description of the related art as well as in the description of the present invention, the terms xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d are used in a manner such that xe2x80x9cat the bottomxe2x80x9d or xe2x80x9cdownxe2x80x9d means in the general direction of the tank filler pipe toward the interior of the tank which is to be closed by the fuel tank closure. Conversely, xe2x80x9ctopxe2x80x9d and xe2x80x9cupxe2x80x9d means the opposite direction, i.e. the axial direction of the filler pipe leading away from the interior of the tank to the outside of the motor vehicle.
A fuel tank closures of the general type claimed in the present invention is generally disclosed in U.S. Pat. No. 5,465,861. This prior art fuel tank closure can remain installed on the mouth of the filler pipe during fueling and allows simple operation by opening and closing of a closure part during the fueling of the motor vehicle. The driver of the motor vehicle is relieved of the task of removing the fuel tank closure from the filler pipe during fueling and also is relieved from replacing the fuel tank closure after fueling the motor vehicle. Operation is so simple that it can also be done by an automatic fueling means.
However, several very important limitations and disadvantages have been found in these prior art fuel tank closures. In such prior art fuel tank closures which remains installed on the mouth of the tank filler pipe during fueling, the fuel nozzle can no longer be inserted as deeply into the tank filler pipe as is possible in conventional closures which are completely removed from mouth of the tank filler pipe during fueling. This can be particularly prevalent and dangerous during manual fueling of the motor vehicle using a conventional fuel nozzle. When such fuel nozzles are not inserted very deeply into the tank filler pipe, there is a potential and serious danger that the automatic final shutoff of the fuel nozzle does not trigger at the right time thereby causing the tank filler pipe to overflow during and after the fueling. Another problem in such prior art system is that it fails to provide an effective and reliable integral inside flap (so-called no-lead flap) which is provided in most vehicles for protecting against fueling with leaded gasoline that is conventionally dispensed from a fuel nozzle with a larger diameter. Because such integral inside flap is not provided, the prior art fuel tank closures necessitates that the no-lead flap be toward the bottom of the tank filler pipe so that the fuel nozzle often does not open the flap when the fuel nozzle is not inserted very deeply into the tank filler pipe. Consequently, this problem poses an additional possibility for fuel spillage during fueling.
Therefore, the primary object of the present invention is to devise a fuel tank closure of the initially mentioned type which is placed on an edge of a mouth of a tank filler pipe and can remain there during the fueling process to enable comfortable and trouble-free refueling.
To achieve this primary object, a fuel tank closure in accordance with the present invention includes a guide pipe which extends into the interior of the tank filler pipe. The guide pipe in accordance with the present invention has a length dimensioned so that the guide pipe extends far into the tank filler pipe. It allows the fuel nozzle to be held and guided reliably and stably to ensure proper filling of the tank. Furthermore, the fuel tank closure in accordance with the present invention also responds to back pressure in the tank filler pipe at the proper time and interrupts the fuel feed from the fuel nozzle. Furthermore the no-lead flap is held in the open position by the guide pipe so that problem-free refueling is ensured even with no-lead flaps which are positioned toward the bottom of the tank filler pipe.
According to another embodiment of the present invention, a fuel tank closure is provided with a guide pipe having a section which tapers in the direction toward the interior of the insert pipe. This section may also be provided with openings so that the fuel vapors which have been displaced from the tank interior during fueling can escape to the outside or be drawn into the refueling means.
In the preferred embodiment, the guide pipe is made from a cylindrical section of steel with a wall thickness between 0.25 and 0.8 mm. In this way, the small annular gap which remains between the nozzle and the narrowest point of the fill channel can be used for accommodating the guide pipe. The stiffness of the guide pipe is enough to keep the inner flap in the open position. In this embodiment, the guide pipe includes a closure part which in the closed state, covers the mouth of the pipe part. The closure part is guided with a restraint by a crank guide such that when the fuel tank closure is opened in the first phase of the opening process, the closure part rises from the mouth of the pipe part in a roughly axial direction of the pipe part. In a subsequent second phase of the opening process, the closure part is swivelled around in the area of the pipe part, or its axial extension, in an axis which lies transversely to the longitudinal direction of the pipe part thereby clearing the mouth of the pipe part. The closure part is coupled to a coupling part which directly or indirectly controls the motion of the closure part. By means of a simple turning or pulling process on the coupling part, the closure part is raised in the first phase of the opening motion in the axial direction and then, is swivelled in a second phase of the opening motion to clear the mouth. By turning in the opposite direction or by releasing the coupling part, the fuel tank closure is closed in the reverse sequence. Therefore, the operation of the fuel tank closure in accordance with the present invention is simple and can also be managed by an automatic refueling means.
In accordance with another embodiment, the fuel tank closure may be provided with a coupling part which is coupled to a rotary ring by form-fit such that the coupling part is connected to be axially movable relative to the rotary ring and yet, prevent rotational motion and be torsionally strong. In this embodiment, the rotary ring engages a sliding sleeve via a screw connection formed by a helical groove and slide pins such that by turning the rotary ring, the sliding sleeve is pushed in the axial direction. In this manner, rotation of the rotary ring can be converted into purely axial displacement of the sliding sleeve thereby resulting in an especially reliable structure for actuating the closure part which is less susceptible to jamming and sticking. The closure part which is made in a cap-shape, is connected to the sliding sleeve via a pivot pin/hole connection and includes two diametrically opposite braces which extend in the axial direction. Thus, the closure part undergoes axial, torsion-free, displacement with the sliding sleeve, but retains a swivelling capacity around an axis which is transverse to the longitudinal axis of the pipe part as defined by the pivot pin/hole connection between the braces and the sliding sleeve.
In accordance with another embodiment of the present invention, the sliding sleeve is joined to the coupling part by form-fit such that the sliding sleeve is fixed with reference to the coupling part in the axial direction, but the coupling part can be turned relative to the sliding sleeve. The result is that the coupling part takes part in the axial displacement of the sliding sleeve when rotary motion is performed. The coupling part can be used in this manner to exert an additional force on the closure part in the direction of the mouth of the pipe part in order to ensure reliable closing.
In accordance with another embodiment of the present invention, the two braces of the closure part surround the pipe part on two sides and a restraint which generates the opening motion of the closure part is provided between the braces and the pipe part. Thus, the restraint may be provided on the inside of the braces and the outside of the pipe part and may be in the form of a crank guide. In one embodiment which is especially simple but very effective in terms of facilitating production, the crank guide is formed by a crank pin/crank groove such that on one of either the brace or the pipe part, there is a pin while on the other of the two parts, there is a groove which accommodates the crank pin. By practicing the present invention, the crank guide can simply comprise a single crank groove and a single crank pin on each of the two sides of the pipe part. In contrast, in order to achieve the swivelling motion of the closure part in the prior art fuel tank closures, a much more complicated arrangement comprising of at least two crank grooves and two crank pins was necessary. This embodiment of the present invention provides significant simplification of the fuel tank closure when the closure is assembled thereby providing a more precise guidance and increased operating reliability of the fuel tank closure. This simplification is enabled by the sliding sleeve executing pure axial motion and transferring it precisely to the braces of the closure part by means of the aforementioned pivot pin/hole connection. The closure part itself has only one degree of freedom of motion relative to the sliding sleeve and more specifically, the closure part swivels around the transverse axis defined by the pivot pin/hole connection. Therefore, sticking of the closure part is substantially eliminated.
According to yet another embodiment, the crank groove of the crank guide includes an axial section which runs in the axial direction, and an adjoining curved section. With the fuel tank closure closed and in the first phase of the opening motion, the crank pin of the crank guide is located in the first groove section while during the second phase of the opening motion, the crank pin enters the curved section.
In another embodiment of the present invention, the pipe part consists of a flange part with a cylindrical section and an insert pipe located within the cylindrical section. A lip seal may be provided between the insert pipe and the cylindrical section of the flange part which surrounds the insert pipe such that the lip seal projects over the edge of the mouth of the pipe part. The peripheral lip seal which is clamped between the two parts and which projects above the edge of the mouth ensures the tightness of the closure part in the closed position since it is protected from being damaged.
In fuel tank closures which are to be retrofitted on the tank filler pipe of a motor vehicle, the insert pipe may be advantageously threaded for screwing into the tank filler pipe. In this manner, the fuel tank closure can then be attached in place like an ordinary tank cap on the tank filler pipe of a motor vehicle. Alternatively, for tank filler pipes which are designed to accommodate a tank cap with a quarter turn fastener, the insert pipe may be provided with a pair of catch hooks in the manner of a quarter turn fastener to enable the attachment of the fuel tank closure on the tank filler pipe in the conventional manner.
According to another embodiment of the present invention, a rotary ring is axially fixed relative to the flange part and is supported to turn relative to the flange part. This guarantees that the rotary ring can execute rotary motion exclusively and is completely decoupled from the axial motion of the other parts.
Similarly, the flange part can be used to support the sliding sleeve so that it may be moved axially but cannot twist relative to the flange part. This in turn, ensures that the sliding sleeve can execute only axial motion relative to the stationary, immovable flange part and not cannot execute rotary motion.
According to another embodiment of the present invention, a plunger pipe is provided which is coupled to the motion of the closure part. The plunger part moves axially in the direction toward the mouth of the tank filler pipe when the fuel tank closure opens and is pressed by the closure part in the direction toward the bottom of the tank filler pipe when the fuel tank closure is closed. In this way the plunger pipe can actuate a valve or an electric switch, by which connections can be established and/or interrupted. For example, many vehicles are equipped with a so-called OBVR (On Board Vapor Recovery System) with an activated charcoal filter which collects the fuel vapors which have been displaced from the fuel tank during fueling and after fuel is delivered to the engine for combustion. In these systems the gas space of the fuel tank during fueling must be connected to the activated charcoal filter and separated after the fueling. Another application of the plunger pipe is as a valve which decouples the fuel equalization tank of the motor vehicle during refueling.
In one advantageous embodiment of the present invention, it is possible to accomplish opening and closing by pulling on a coupling part in the axial direction. To accomplish this purpose, the sliding sleeve may be supported to move axially together with the coupling part against the force of a pretensioning spring.
According to another advantageous embodiment, the side wall of the pipe part may also be provided with an overpressure/underpressure valve.
These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the invention when viewed in conjunction with the accompanying drawings.